Coaxial (coax) cable is nearly ubiquitous in today's technology-based, information-driven society. It is used in a wide variety of applications, including broadband Internet and cable television, as well as specialty applications, including a wide variety of radio frequency (RF) antennae applications.
Coaxial cable generally includes a central axial conductor element and one or more outer conductor elements wrapped concentrically around the central axial conductor. A low-loss, high dielectric insulation material separates the conductors. In most applications, an outer insulating cover is provided to shield the outer conductor element so as to provide insulations and physical protections to all inner components of the coaxial cable. The concentric conductor may be a single strand of conductive wire that is wrapped helically around the insulating material that covers the central, axial conductor element, or more typically, a fine wire braid or mesh fashioned from conductive materials such as copper, aluminum and aluminum alloys, stainless steel, metallized polymer materials, and the like.
Throughout all sectors of the economy, and throughout all facets of the consumer, mass-market culture, coaxial cable has penetrated virtually every crevice of infrastructure to deliver broadband Internet connections or wide band radio frequency information for computers, radios and television. Increasingly, coaxial cable networks are the preferred medium for a majority of citizens who wish to access news, entertainment and information, as well as perform myriad daily tasks such as shopping, paying bills, communicating with family, friends and business contacts.
Because modern society is so dependent on information connections via coaxial cable networks, it is important that these networks be dependable and reliable, as well as adaptable for expansions and modifications, or repairs when storms, fires or other events damage them. Whenever these expansions, modifications or repairs are required, it is always necessary to join, or splice, the terminal ends of separate, coaxial cables. Sometimes, hundreds or even thousand of splices are required to meet the demands of a particular upgrade or repair. Under any circumstance, the splicing of coaxial cable termini is labor intensive. Moreover, because of the delicate and fragile characteristics of certain aspects of coaxial cable design, the splicing requires a specific skill set.
Coaxial cable generally includes a central axial conductor element and an outer conductor element wrapped concentrically around the central element. A low-loss, high dielectric insulation material separates the two conductors. In most applications, an outer insulating cover is provided to shield the outer conductor element so as to provide insulation and physical protection to all inner components of the coaxial cable. The concentric conductor may be a single strand of conductive wire that is wrapped helically around the insulating material that covers the central, axial conductor element, or, more typically, a fine wire braid or mesh fashioned from an aluminum alloy.
In order for coaxial cable to function properly, it is critical that the insulation between the two conductive elements be maintained, and that the isolation distance separating the two conductive elements be constant. This controlled insulation and separation allows the outer conductive element to serve as a shield to protect the inner conductive element from electromagnetic, or radio frequency interference (RFI). If the inner conductive element is not properly shielded from RFI, the communication signals transported along the inner conductive element will be degraded, modulated with undesirable changes, or completely interrupted.
When the connections along a length of coaxial cable are properly made, the cable is essentially shielded from interference of RFI. This shielding is made possible because the outer conductive element carries a current that is precisely the reverse of the inner conductive element, thereby creating a pair of magnetic fields that cancel each other out. However, if the termini of the outer conductive elements are not precisely and uniformly connected so as to maintain the aforementioned insulation and separation parameters, little or no reverse current will flow along the outer element and the shielding will collapse. Without proper shielding, the signal current traveling along the inner conductive element will emit electromagnetic radiation to the atmosphere. At the same time, extraneous electromagnetic radiation from the atmosphere will be absorbed by the inner conductive element.
Some applications for coaxial cable installations need the benefit of improved mechanical and electrical characteristics. Certain applications either require, or benefit substantially from, a capability to withstand mechanical pull strength between the cable and connector that meets or exceeds a specified pull force. This characteristic is known as high pull strength, and allows the cable to be pulled through wire channels and special installations, without causing damage to the cable or to the electrical connection between the cable and the connector.
Additionally, some applications require an extremely low loss electrical characteristic. Power loss, or attenuations, occurs whenever power is transmitted within a cable, and is usually identified in decibels per unit length of cable. Attenuation can be caused by resistive heating of the conductors within the cable, dielectric loss, and radiated loss from power dissipated from the cable into the surroundings. In general, attenuations increase with frequency, and is dependent on a number of factors, including the size and type of conductors, the dielectric material in the cable, the propensity of the dielectric material to absorb moisture, and the type and quality of the shielding.